1. Field of Invention
The invention relates to an emergency shutdown system, and more particularly to a logic circuit that is reconfigurable to execute an emergency response using a predefined user strategy.
2. Description of Related Art
All emergency shutdown systems are governed by a certification standard, IEC 61508, which outlines the requirements for both software and hardware used to implement an emergency shutdown system. IEC 61508 is directed to the functional safety of electrical/electronic/programmable electronic safety related systems.
IEC 61508 governs all aspects of the emergency shutdown system from conception, design, implementation, operation and maintenance. Specifically, the standard provides a method for the development of safety requirements necessary to achieve the required functional safety for the system. The main concern for the safety standard is a system failure that could have an impact on the safety of persons or the environment.
The purpose of the emergency shutdown system is to reduce hazard and risk potentials with the operation of electronic, hydraulic, and electric devices.
Typically, an emergency shutdown system is implemented by a computer-based system. This computer-based system requires certification for both the software and hardware elements of the emergency shutdown system as well as any other software the runs on the computer; additionally any changes to either the software or hardware elements. Certification is also required for the process of creating hardware and software.
The certification process is designed to reduce the number of failures in the emergency shutdown system caused by random hardware, software, or integration failures.
The certification process is time consuming and requires a significant amount of overhead, especially where both the software and the hardware must be certified. It is particularly difficult to achieve a certification in systems that include significant software components, as there are numerous requirements for the software.
Accordingly, there is a need to provide an emergency shutdown system that complies with the IEC 61508 that can be certified in a quick and efficient manner.